After going to the Crucible and talking to Mad-Dog, you can go to Oakfield to investigate a problem at The Temple of Light. There, the Head Abbot tells that they're in need of a protector once more. It seems that the vile cultists from The Temple of Shadows intend to poison the holy water in the Wellspring Cave, which will in turn cause the Golden Oak to die and cause the downfall of The Temple of Light - maybe even all of Oakfield. The player is to journey into the cave and protect the water "at all costs".

Enter the Wellspring Cave via the same entrance the player and Hannah entered not so long ago. When the player arrives in the left water chamber, they'll discover a shadow-worshipper busy performing a dark ritual. The player should be able to take him out with one hit, but they'll also have to contend with a handful of highwaymen protectors in the room. Finish them off too, then backtrack to the central area and head into the right water chamber. Another robed shadow-worshipper and his highwaymen protectors await the player. Slay them, as well.

All that's left is the central water chamber. There, they player will encounter Cornelius Grim, leader of The Temple of Shadows. The vile priest has a ring of blades that surrounds him, making him invulnerable for the time being. The player will have to deal with yet another group of highwaymen and two waves of hollow men before Cornelius can be subjected to physical harm. With the blades dissipated and his minions dead, Cornelius transforms into a shadow and charges. Hit him with whatever weapons or spells and he'll go down without much of a fight. Once he's defeated, a Temple of Light monk enters the chamber and thanks the player for ridding Albion of a great evil. This earns the player 750 renown points and the Temple of Light Seal trophy.

Forever Changed: Completing this quest will alter the layout of Oakfield, so make sure to fully explore the region before leaving for the Spire.

After you come back from The Spire, the village and the Temple will have expanded greatly, and the Temple will also be available for sale. This comes with the ability to acquire the "Chosen One" title for free from any Town Crier.

If the Hero does not protect the Golden Oak, then upon returning from The Spire, Oakfield will have fallen into darkness and hollow men spawn in numerous locations. This will be the same as if you did the Oakfield Massacre quest.Theresa explains that choosing to do nothing is a choice that has consequences as well.

This quest is the opposite of the Oakfield Massacre quest, when if completed, the Temple of Light will have been destroyed, and you have the ability to buy the Temple of Shadows.

Should you have become a Shadow Worshipper and obtained the Maelstrom before you do this quest, the Temple of Light monks will not react to you any differently. Cornelius Grim however, will call you a traitor and say that no one betrays the Temple of Shadows and lives.